Hydralazine hydrochloride

Chemical Name 1 2H)-phthalazinone hydrazone hydrochloride Common Name 1-hydrazinophthalazine hydrochloride Structural Formula  

Trade Name Manufacturer Country Year Introduced 

30 parts by weight of phthalazone are converted to Tchlorophthalazine by the method described in Ber. d. deutsch. chem. Ges., vol 26, page 521 (1893). The freshly obtained yet moist chloro compound is heated on the water bath for two hours in a mixture of 100 parts by volume of ethyl alcohol and 90 parts by volume of hydrazine hydrate. Preferably after filtering, 1-hydrazino-phthalazine crystallizes out in yellow needles on cooling. 

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Propectin (Maruishi) Solesorin (Hishiyama) USA Hydralazine Hydrochloride (SoloPak)... 

Hydralazine hydrochloride 1 0-20 mg IV 10-40 mgIM 1 0-20 minutes 20-30 minutes 1-4 hours IV 4-6 hours IM Tachycardia, flushing, headache, vomiting, aggravation of angina Eclampsia... 

Pernicious anemia Alzheimer s disease Hydralazine hydrochloride... 

The Chemical Abstracts name for hydralazine hydrochloride is l(2H)-phthalazinone hydrazone monohydrochloride, starting with volume 80 previously the name 1-hydrazino-phthalazine monohydrochloride was used. The CAS Registry No. is [304-20-1] for the hydrochloride salt, [86-54-4] for the base. 

Hydralazine hydrochloride is a white to off-white odorless crystalline powder. 

The infrared spectrum of hydralazine hydrochloride (Figure 1) was obtained with a Beckman IR-12 spectrophotometer. A mineral oil dispersion between potassium bromide plates was scanned from 420 to 4000 cm-1, and a thicker layer of the dispersion, supported on polyethylene film,... 

The mineral oil absorption at 2800 to 3000 cm- 1 and at 1460 cm- obscures absorption bands of hydralazine hydrochloride at 2810, 2920, and 2970 cm-1 (N-H+ stretch) and a weak sharp band at 1470 cm- these bands can be observed in potassium bromide dispersion spectra. The bands at 1070 and 1082 cm-1 tend to merge into a single band in potassium bromide dispersion spectra. 

The infrared spectrum of hydralazine hydrochloride base in a potassium bromide dispersion (Figure 2) was recorded from 400 to 4000 cm-1, and the 200 to 550 cm-1 region was obtained from a mineral oil dispersion supported on polyethylene film. The spectra of potassium bromide dispersions of the base are qualitatively identical to those of mineral oil dispersions. The assignment of absorption bands in the spectrum of the base is similar+to that of the hydrochloride except for the presence of N-H stretch absorption in the latter. A spectrum of the base has been published (6). 

Figure 3 is the ultraviolet absorption spectrum of hydralazine hydrochloride in water solution, run on a Cary Model 14 spectrophotometer. The solution contained 9-9 mg of hydralazine hydrochloride per liter, and was run against water (1 cm cells). The discontinuity in the spectrum at 219 nm is a change of absorption scale the absorbance scale range is 0.0 to 1.0 for the wavelength range 350 to... 

Figure 1. Infrared Absorption Spectrum of Hydralazine Hydrochloride, Mineral Oil Mull...

Figure 4 shows the low resolution mass spectrum of hydralazine hydrochloride. The data were obtained with an LKB 9000S mass spectrometer, with an ionization voltage of 70 eV, source temperature 250°C. Some of the peaks may be assigned as follows C13) ... 

The NMR spectrum shown in Figure 5 was obtained by dissolving hydralazine hydrochloride in deuterium oxide containing 3-(trimethylsilyl)-1-propane-sulfonic acid sodium salt (DSS). The series of peaks at 0, 0.6, 1.8, and 3 ppm are all due to the DSS. The peak at 4.8 ppm is due to HDO which forms on exchange with the solvent and the peaks at 8.01 and 8.61 ppm are due to the aromatic protons. The NMR spectrum of the base (Figure 6) was obtained in a 1 1 mixture of dimethylsulfoxide-d,- deuterochloroform. 

X-ray powder diffraction data for hydralazine hydrochloride and hydralazine base are given in Table 1. 

Kuhnert-Brandstfitter et al (7) reported the microscopic hot-stage characterization of hydralazine hydrochloride. Above 210°C, small rods, granules, and prisms sublime. The melting point is 268-275°C. Gas bubbles are evolved as melting begins, and melting proceeds with... 

Figure Nuclear Magnetic Resonance Spectrum of Hydralazine Hydrochloride.

Figure 7 Differential Thermal Analysis Curve of Hydralazine Hydrochloride.

The melting point of hydralazine hydrochloride is near 273°C, that of the base is near 173°C. Melting points reported in the literature are as follows ... 

Hydralazine hydrochloride is quite stable as the crystalline solid. At room temperature, it is stable in distilled water solution for weeks (32). In aqueous... 

Hydralazine hydrochloride is rapidly metabolized and excreted. Experiments with carbon-14 labeled drug in humans indicated that less than 10 percent of the intact drug was excreted (36). Within 5 days after a dose, 83 to 89 percent was excreted in the urine and 9 to 12 percent in the feces. Of the material excreted in the urine, 96 percent was recovered in the first 24 hours. Individuals who are slow acetylators exhibit higher hydralazine blood levels than fast acetylators, for the same dose (37) ... 

Hydralazine hydrochloride can be easily identified by the physical properties described in Section 2 above. 

Naik et al (11) extracted hydralazine hydrochloride from tablets with 50 percent aqueous methanol and mixed a portion of the extract with 99 volumes of concentrated sulfuric acid to obtain fluorescence at 353 nm with excitation at 320 nm. The fluorescence intensity varied linearly with concentration in the range 2 to 8 ig hydralazine hydrochloride per ml. Injections were analyzed similarly. 

Perel man and Evstratova (65) titrated hydralazine hydrochloride in dimethylformamide solution to a potentio-metric end-point with sodium methoxide solution. 

Artamanov et al (18) determined hydralazine hydrochloride by conductometric titration with sodium hydroxide solution. 

Goryacheva and Prikhodkina (66) titrated hydralazine from tablets with N-bromosuccinimide solution. One mole of hydralazine hydrochloride was equivalent to 2 moles of N-bromosuccinimide. Methyl red was used as the indicator. 

Smith et al (76,773 analyzed hydralazine in a drug mixture containing hydralazine hydrochloride, hydrochlorothiazide, and an impurity derived from the latter. The column was 1 m x 2.1 mm (ID) stainless steel, packed with a strong anion exchanger on 30 Jm Zipax . The mobile phase was pH 9 2 borate buffer containing 0.005M sodium sulfate (5 methanol), at 1.7 ml per minute. Detection was by ultraviolet absorption at 25 nm. 

Diphenhydramine hydrochloride, 3,173 Diphenoxylate hydrochloride, 7,149 Disulflram, 4, 168 Dobutamine hydrochloride, 8,139 Droperidol, 7,171 Echothiophate iodide, 3,233 Epinephrine, 7, 193 Ergotamine tartrate, 6,113 Erythromycin, 8,139 Erythromycin estolate, 1, 101 2, 573 Estradiol valerate, 4,192 Ethambutol hydrochloride, 7,231 Ethynodiol diacetate, 3,253 Fenoprofen calcium, 6,161 Flucytosine, 5,115 Fludrocortisone acetate, 3, 281 Fluorouracil, 2,221 Fluoxymesterone, 7,251 Fluphenazine enanthate, 2, 245 4,523 Fluphenazine hydrochloride, 2,263 4,518 Gluthethimide,5,139 Gramicidin, 8,179 Griseofulvin, 8,219 Halcinonide, 8,251 Halothane, 1, 119 2,573 Hexetidine, 7,277 Hydralazine hydrochloride, 8,283 Hydroflumethiazide, 7,297 Hydroxyprogesterone caproate, 4,209 Hydroxyzine dihydrochloride, 7,319 Iodipamide, 3,333 Isocarboxazid, 2, 295... 

Potassium iodate is a fairly strong oxidizing agent that may be used in the assay of a number of pharmaceutical substances, for instance benzalkonium chloride, cetrimide, hydralazine hydrochloride, potassium iodide, phenylhydrazine hydrochloride, semicarbazide hydrochloride and the like. Under appropriate experimental parameters the iodate reacts quantitatively with both iodides and iodine. It is, however, interesting to observe here that the iodate titrations may be carried out effectively in the presence of saturated organic acids, alcohol and a host of other organic substances. 

A host of other pharmaceutical substances, namely cetrimide, hydralazine hydrochloride, phenylhydrazine hydrochloride may be assayed by titration with potassium iodate as mentioned in Table 13.3. 

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